A typical measurement device designed to analyze tri-state logic systems which include a ground-referenced attenuator will show a logical "0" when the probe tip of the device is floating (i.e., open). While this situation is not a problem per se, it does indicate a logical state that doesn't really exist. In other words, the device will show "0," instead of "open," or some similar indication that the probe is not attached to anything. Another problem with this device, is that it will cause a floating data bus to be "tri-stated" when the probe is attached to the bus. That is, the bus is pulled down by the device because the attenuator is ground-referenced.